Composition having sealing and sound dampening properties and methods related thereto

ABSTRACT

A composition having sealing and sound dampening properties is disclosed which comprises one or more polyepoxides comprising at least two epoxide groups per molecule; a thermoplastic polyester polymer; a curing agent adapted to react with the polyepoxides; inorganic particles having an oil absorption value of less than 70; and inorganic microparticles different from the previously mentioned inorganic particles, the inorganic microparticles having an average particle size prior to incorporation into the composition ranging from 0.5 to 200 microns. Multilayer composites, coated substrates, and methods for forming sound dampening coatings on a metallic substrate are also provided.

FIELD OF THE INVENTION

[0001] The present invention relates to compositions having sealing andsound dampening properties and related processes. In particular, thepresent invention relates to compositions having sealing and sounddampening properties that can be applied in a body shop via spraying.

BACKGROUND & DISCUSSION

[0002] Sealants and sound dampeners typically are applied to a varietyof areas in automobile bodies such as interior floor pans, firewalls,decklids, and is between the inner and outer panels of doors.Conventionally, sealants have comprised plastisols that can be appliedbetween and upon metal seams, welds and within hollow cavities ofautobodies. Generally, sealants are used to impart structural integrityand to create a barrier against dirt and exhaust gases. Sound dampenerstypically are pre-cut pieces of fibrous asphaltic material or aluminumconstrained butylene rubber used to dampen road and engine noise thatcan be transmitted through the autobody substrates.

[0003] A sprayable coating composition having vibration and harsh noisereduction or absorption properties is disclosed in InternationalApplication WO 99/16840. The sprayable coating composition comprises amixture of flexible epoxy resins and rigid epoxy resins. The flexibleepoxy resins are defined as those having elastomeric chains in thebackbone; and the rigid epoxy resins are defined as those epoxy resinshaving bisphenol moieties in the backbone. The mixture of the flexibleand rigid epoxy resins should be such that the peak glass transitiontemperature of the composition is 10° C. or greater.

[0004] Conventionally, sealants and sound dampeners are applied to someautomotive parts in the paint shop area of an automobile assembly plantwhich is typically located downstream from the electrocoat tank in theautomotive coating process. The application of sealants and sounddampeners in the paint shop area can result in fingerprints, dirt and/oroverspray on the automotive part which must be removed prior tosubsequent application of primer and/or top coatings.

[0005] The body shop is the area of an automobile assembly plant whichis located upstream from and can include the electrocoat tank. In a bodyshop, any dirt, fingerprints, and/or overspray on the automotive partresulting from the application of sealants and sound dampeners could bewashed away in the pretreatment wash cycle. It, therefore, would beadvantageous to provide a composition having sealing and sound dampeningproperties suitable for application in the body shop area of theautomotive assembly plants.

SUMMARY OF THE INVENTION

[0006] In one embodiment, the present invention provides a compositionhaving improved sealing and sound dampening properties comprising:

[0007] (a) one or more polyepoxides comprising at least two epoxidegroups per molecule;

[0008] (b) a thermoplastic polyester polymer;

[0009] (c) a curing agent adapted to react with the polyepoxides;

[0010] (d) inorganic particles having an oil absorption value of lessthan 70 as determined in accordance with ASTM D 281-95; and

[0011] (e) inorganic microparticles different from the inorganicparticles (d), the inorganic microparticles having an average particlesize prior to incorporation into the composition ranging from 0.5 to 200microns.

[0012] In another embodiment, the present invention provides amultilayer composite comprising a weldable primer layer formed from aweldable primer composition, and a second layer having improved sealingand sound dampening properties formed from a second composition over atleast a portion of the weldable primer layer, the second compositioncomprising:

[0013] (a) one or more polyepoxides comprising at least two epoxidegroups per molecule;

[0014] (b) a thermoplastic polyester polymer;

[0015] (c) a curing agent adapted to react with the polyepoxide (a);

[0016] (d) inorganic particles having an oil absorption value of lessthan 70 as determined in accordance with ASTM D 281-95; and

[0017] (e) inorganic microparticles different from the inorganicparticles (d), the inorganic microparticles having an average particlesize prior to incorporation into the composition ranging from 0.5 to 200microns.

[0018] In yet another embodiment, the invention provides a coatedmetallic substrate comprising:

[0019] a metallic substrate, and a composition having sealing and sounddampening properties over at least a portion of the substrate, saidcomposition comprising:

[0020] (a) one or more polyepoxides comprising at least two epoxidegroups per molecule;

[0021] (b) a thermoplastic polyester polymer;

[0022] (c) a curing agent adapted to react with the polyepoxides (a);

[0023] (d) inorganic particles having an oil absorption value of lessthan 70 as determined in accordance with ASTM D 281-95; and

[0024] (e) inorganic microparticles different from the inorganicparticles (d), the inorganic microparticles having an average particlesize prior to incorporation into the composition ranging from 0.5 to 200microns.

[0025] Additionally, the present invention provides a coated metallicsubstrate comprising:

[0026] a metallic substrate;

[0027] a weldable primer layer formed from a weldable primer compositiondeposited over at least a portion of the substrate; and

[0028] a second layer formed from a second composition having sealingand sound dampening properties deposited over at least a portion of theweldable primer layer, the second composition comprising:

[0029] (a) one or more polyepoxides comprising at least two epoxidegroups per molecule;

[0030] (b) a thermoplastic polyester polymer;

[0031] (c) a curing agent adapted to react with the polyepoxides (a);

[0032] (d) inorganic particles having an oil absorption of less than 70;and

[0033] (e) inorganic microparticles different from the inorganicparticles (d), the inorganic microparticles having an average particlesize prior to incorporation into the composition ranging from 0.5 to 200microns.

[0034] In another embodiment, the invention provides a method forforming a coating having sealing and sound dampening properties on ametallic substrate comprising the steps of:

[0035] (a) providing a metallic substrate having two major surfaces,

[0036] (b) applying a composition to at least a portion of one of themajor surfaces of the substrate, said composition comprising:

[0037] (1) one or more polyepoxides comprising at least two epoxidegroups per molecule;

[0038] (2) a thermoplastic polyester polymer;

[0039] (3) a curing agent adapted to react with the polyepoxides (1);

[0040] (4) inorganic particles having an oil absorption value of lessthan 70 as determined in accordance with ASTM D 281-95; and

[0041] (5) inorganic microparticles different from the inorganicparticles (4), the inorganic microparticles having an average particlesize prior to incorporation into the composition ranging from 0.5 to 200microns; and

[0042] (c) curing the applied composition, wherein the coated substrateof step (c) has a sound dampening value greater than 0.030 Oberstdissipation factor as measured at 200 Hz at 25° C. in accordance withASTM E-756-98.

[0043] In yet another embodiment, the invention provides a compositionhaving sealing and sound dampening properties comprising:

[0044] (a) one or more polyepoxides comprising at least two epoxidegroups;

[0045] (b) a thermoplastic polyester polymer;

[0046] (c) a curing agent adapted to react with the polyepoxide (a); and

[0047] (d) inorganic particles having an oil absorption value of lessthan 70 as determined in accordance with ASTM D 281-95, the improvementcomprising the inclusion in the composition of inorganic microparticlesdifferent from the inorganic particles (d) in an amount sufficient toprovide corrosion resistance properties as measured in accordance withChrysler Test Method LP-463PB-10-01 which are superior to the corrosionresistance properties of the same composition which does not containsaid inorganic microparticles, the inorganic microparticles having anaverage particle size prior to incorporation into the compositionranging from 0.5 to 200 microns.

DETAILED DESCRIPTION OF THE INVENTION

[0048] Other than in the operating examples, or where otherwiseindicated, all numbers expressing quantities of ingredients, reactionconditions and so forth used in the specification and claims are to beunderstood as being modified in all instances by the term “about”.Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present invention. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

[0049] Notwithstanding that the numerical ranges and parameters settingforth the broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical values, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

[0050] Also, it should be understood that any numerical range recitedherein is intended to include all sub-ranges subsumed therein. Forexample, a range of “1 to 10” is intended to include all sub-rangesbetween and including the recited minimum value of 1 and the recitedmaximum value of 10, that is, having a minimum value equal to or greaterthan 1 and a maximum value of equal to or less than 10.

[0051] The present invention is directed to a composition having sealingand sound dampening properties. The composition comprises one or morepolyepoxides comprising two or more epoxide groups per molecule, athermoplastic polyester polymer, a curing agent adapted to react withthe previously mentioned polyepoxide, inorganic particles having an oilabsorption value of less than 70, and inorganic microparticles differentfrom the previously mentioned inorganic particles, the inorganicmicroparticles having an average particle size prior to incorporationinto the composition ranging from 0.5 to 200 microns.

[0052] The one or more polyepoxides comprise two or more epoxide groupsper molecule. As used herein, the term “polyepoxide” refers to anyepoxide group-containing compound having two or more epoxide groups permolecule. The polyepoxides in the present invention can be saturated orunsaturated, cyclic or acyclic, aliphatic, alicyclic, aromatic orheterocyclic and can comprise substituents such as halogen, hydroxyl andether groups. Polyepoxides containing the aforementioned substituentgroups can be obtained via well known methods.

[0053] Several types of polyepoxides can be used in the presentinvention for example, polyglycidyl ethers of polyhydric alcohols,polyglycidyl esters of polycarboxylic acids, inter alia, can beemployed. Epoxy polyethers can be obtained by reacting an epihalohydrin,such as epichlorohydrin or epibromohydrin, with a polyphenol in thepresence of an alkali. Suitable polyphenols include resorcinol,catechol, hydroquinone, bis(4-hydroxyphenyl)-2,2-propane also known asbisphenol A, bis(4-hydroxyphenyl)-1,1-isobutane,4,4-dihydroxybenzophenone, bis(4-hydroxyphenol)-1,1-ethane,bis(2-hydroxyphenyl)-methane, and 1,5-hydroxynaphthalene, and thediglycidyl ether of bisphenol A.

[0054] Suitable polyhydric alcohols are ethylene glycol, diethyleneglycol, triethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol,1,5-pentanediol, 1,2,6-hexanetriol, glycerol, trimethylolpropane, andbis(4-hydroxycyclohexyl)-2,2-propane.

[0055] Suitable polyglycidyl esters of a polycarboxylic acids can beproduced by the reaction of epichlorohydrin or similar epoxy compoundwith an aliphatic or aromatic polycarboxylic acid such as oxalic acid,succinic acid, glutaric acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and dimerized linoleic acid.

[0056] Also suitable are the polyepoxides derived by epoxidating anolefinically unsaturated alicyclic compound. Oxygen and selected metalcatalysts, perbenzoic acid, acid-aldehyde monoperacetate, or peraceticacid can be used for the epoxidation. Examples of these polyepoxidesinclude epoxy alicyclic ethers and esters which are well known in theart.

[0057] Polyepoxides which contain oxyalkylene groups in the epoxymolecule are also suitable for use in the present invention. Theoxyalkylene groups can be pendant to the main molecular chain of thepolyepoxide or part of the main chain itself, and have the generalformula: —O—R, where R is alkyl and pendant or links the ether oxygenwith the rest of the chain. The chain length of the oxyalkylene group,the nature of the epoxy, and the degree of water solubility desireddetermines the proportion of oxyalkylene groups in the polyepoxide.

[0058] Also suitable are the epoxy novolac resins obtained by reactingan epihalohydrin with the condensation product of aldehyde andmonohydric or polyhydric phenols. For example, an epoxy novolac resincan be formed from the reaction of epichlorohydrin andphenol-formaldehyde condensate. Mixtures of polyepoxides can be used aswell.

[0059] The polyepoxide (a) can be present in the composition of thepresent invention in an amount ranging from 15 to 50 weight percent,usually 20 to 50 weight percent, and typically 25 to 45 weight percent,based on the total weight of the composition. Generally, the epoxideequivalent weight can range from 70 to 4,000.

[0060] The composition of the present invention also includes athermoplastic polyester polymer (b). The term “polyester” as used hereinwith respect to the thermoplastic polyester polymer is intended toinclude resins which contain oil or fatty acid modifications, forexample, alkyd resins. Suitable thermoplastic polyester polymerstypically contain no more than 10 percent by weight of aromatic units,the percentage based upon the total weight of all of the ingredientsused to prepare the polyester. As used herein, an “aromatic unit” isintended to mean one or more aromatic rings such as those generallyderived from aromatic acids or anhydrides, for example, phthalic acid,isophthalic acid or terephthalic acid.

[0061] The thermoplastic polyester polymer usually is insoluble in thepreviously mentioned polyepoxide (a). In other words, when thethermoplastic polyester polymer is mixed with the polyepoxide, a hazy,heterogeneous phase will result. The term “thermoplastic” connotes thatthe polyester is substantially non-reactive with the other componentspresent in the composition.

[0062] In a particular embodiment of the present invention, thethermoplastic polyester polymer is substantially saturated. Thesaturated polyesters can contain some percentage of unsaturated unitsprovided that the thermoplastic polyester is not reactive with the othercomponents of the curable sound dampening composition. For example, thesaturated thermoplastic polyester may contain 10 percent or less ofunsaturated units by weight, the percentage being based on the totalweight of all the ingredients used to prepare the thermoplasticpolyester.

[0063] Suitable thermoplastic polyesters can be prepared frompolyfunctional acids and polyhydric alcohols by methods well known inthe art. Non-limiting examples of suitable polyfunctional acids includeadipic acid, azelaic acid, glutaric acid, phthalic acid, sebacic acidand the anhydrides thereof. Unsaturated polyfunctional acids such asmaleic acid and fumaric acid can be used to introduce unsaturation ifdesired. Suitable non-limiting examples of polyhydric alcohols includeethylene glycol, propylene glycol, diethylene glycol, dipropyleneglycol, butylene glycol, glycerol, trimethylolpropane, pentaerythritoland sorbitol.

[0064] Generally, when the thermoplastic polyester is prepared from thecompounds described above, one or more of the diols and one or more ofthe diacids is charged into a reaction vessel. The reaction vessel isheated to a temperature ranging from about 200° C. to 300° C., andexcess water is removed via distillation. Solvents such as xylene ortoluene can be employed in the reaction mixture to help remove water byazeotropic distillation. An esterification catalyst such as dibutyltinoxide or butyl stannoic acid can be used to increase the rate ofreaction. Similarly, functional derivatives of the diacids such asesters anhydrides or acid chlorides can be employed.

[0065] The thermoplastic polyester polymer can be present in theinventive composition in an amount ranging from 3 to 30 weight percent,often from 5 to 25 weight percent, and typically from 7 to 20 weightpercent, based on the total formula weight of the composition.Additionally, the thermoplastic polyester polymer can have a weightaverage molecular weight of less than 10,000, and typically from 400 to8,000 as determined by gel permeation chromatography (GPC) using adifferential refractometer. The number average molecular weight of thethermoplastic polyester polymer can range from 400 to 5,000.

[0066] The composition of the present invention having sealing and sounddampening properties further comprises a curing agent (c) capable ofreacting with the previously mentioned polyepoxides. Suitable curingagents include, for example, aliphatic, cycloaliphatic and aromaticpolyfunctional amines and polyamides.

[0067] Examples of suitable amines include ethylene diamine, diethylenetriamine, triethylene tetraamine, tetraethylene pentamine,1,4-diaminobutane; 1,3-diaminobutane, hexamethylene diamine,3-(N-isopropylamino) propylamine, diaminocyclohexane, andpolyoxypropyleneamines. Aromatic amines can also be used in the presentinvention. Examples of suitable aromatic amines include metaphenylenediamine, p, p′-methylene dianiline, and 1,4-aminonaphthalene. Latentcuring agents, i.e., those which are inactive until activated by theapplication of heat, can also be used. Examples of latent curing agentsinclude boron trifluoride monoethylamine complex, boron trifluoridediethylamine complex, boron trifluoride triethylamine complex, borontrifluoride pyridine complex, boron trifluoride benzyldimethylaminecomplex, boron trifluoride benzylamine, boron trifluoride etherate, anddicyandiamide.

[0068] Suitable polyamide curing agents include those derived from fattyacids, dimerized fatty acids, polymeric fatty acids and, aliphaticpolyamines. Examples of suitable polyamide curing agents are VERSAMID®220 and 125 available from Cognis Corporation.

[0069] The curing agent (c) can be present in the composition of thepresent invention in an amount ranging from 1 to 50 percent by weight,often from 3 to 15 percent by weight, and typically from 0.5 to 5percent by weight, based on the total weight of the composition.

[0070] The composition of the present invention having sealing and sounddampening properties also comprises inorganic particles (d). Theinorganic particles can have an oil absorption value of less than orequal to 70, and typically less than or equal to 60. For purposes of thepresent invention, the “oil absorption value” of the inorganic particlesshould be understood as that determined in accordance with ASTM D281-95, Standard Test Method for Oil Absorption of Pigment by SpatulaRub-Out.

[0071] The inorganic particles can include inorganic materials such asmica, calcium carbonate, dolomite, talc, and calcium metasilicate, forexample, wollastonite. The inorganic particles can have a variety ofmorphologies, including a spherical morphology, an irregular morphology,a platy morphology, a needle shaped morphology, or mixtures thereof.Also, the inorganic particles can have a particle size prior toincorporation into the composition ranging from 5 to 200 microns, andtypically from 20 to 80 microns.

[0072] The inorganic particles (d) can be present in the composition ofthe present invention in an amount ranging from 5 to 65 weight percent,often from 15 to 50 weight percent, and typically from 20 to 40 weightpercent, based on the total weight of the composition.

[0073] The composition of the present invention having sealing and sounddampening properties comprises inorganic microparticles (e) which aredifferent from and in addition to the inorganic particles describedabove. Suitable inorganic microparticles include colloidal silica,calcium modified precipitated silica, ion exchanged silica gel,colloidal alumina, and mixtures thereof. Prior to incorporation into thecomposition, the average particle size of such inorganic microparticlescan range from 0.5 to 200 microns, usually from 3 to 150 microns, andtypically from 10 to 100 microns. The inorganic microparticles can bepresent in the composition of the present invention in an amount rangingfrom 0.1 to 5 weight percent, and typically from 0.5 to 3 weight percentbased on the total weight of the composition.

[0074] A variety of optional ingredients also can be included in thecomposition of the present invention. For example, the present inventioncan include pigments, reinforcement materials, thixotropes,plasticizers, extenders, stabilizers, antioxidants, at least onepolyglycidyl ester of a polycarboxylic acid different from thepolyepoxide (a), at least one alkylene diene copolymer, and one or moremetallic compounds.

[0075] In one embodiment of the present invention, the composition ofthe present invention having sealing and sound dampening propertiesfurther comprises a polyglycidyl ester of a polycarboxylic aciddifferent from the polyepoxide (a). An example of a polyglycidyl esterof a polycarboxylic acid is the reaction product of an epihalohydrin anda dimerized fatty acid such as the reaction product of epichlorohydrinand dimerized linoleic acid. The polyglycidyl ester can be present inthe composition in an amount of up to 20 weight percent, and typicallyfrom 2 to 16 weight percent, based on the total weight of thecomposition.

[0076] The composition of the present invention having sealing and sounddampening properties optionally can comprise an alkylene dienecopolymer, for example, an ethylene propylene diene terpolymer. Theweight average molecular weight of suitable alkylene diene copolymerscan range from 1,000 to 15,000, and typically from 3,000 to 10,000 asdetermined by GPC using a polystyrene standard. The number averagemolecular weight of the alkylene diene copolymer can range from 6,000 to7,000. When used, the alkylene diene copolymer can be present in thecomposition of the present invention in an amount of up to 10 weightpercent, and typically from 1 to 7 weight percent based on the totalweight of the composition.

[0077] In one particular embodiment of the present invention, thecomposition of the present invention comprises one or more metalliccompounds. The metallic compound(s) suitable for use in the presentinvention comprise a metal cation and a counterion, i.e., an anion.Suitable metal cations include those selected from zinc, aluminum,magnesium, calcium, strontium, titanium, zirconium, cesium, and yttrium.Suitable anions include those selected from phosphates, polyphosphates,phosphites, molybdates, sulfonates, tungstates, borates, borosilicates,silicates, and cyanamides. In one embodiment of the present invention,the metal compound is selected from a zinc compound, a calcium compound,and mixtures thereof. The metallic compound(s) can be present in theinventive composition in an amount ranging from 0.1 to 5 weight percent,often from 0.3 to 4 weight percent, and typically from 0.5 to 3 weightpercent based on the total weight of the composition.

[0078] Often times, the composition of the present invention will beapplied to a metallic substrate. As used herein, “substrate” refers to abare (i.e., uncoated or untreated) substrate, to a treated substrate,or, alternatively, to a previously coated substrate. Also the“substrate” can include a metal substrate which has been previouslytreated and/or coated with a combination of pretreatments, conversioncoatings and/or primer coatings. Metallic substrates used in the presentinvention encompass a number of metallic substrates known in the art,including, ferrous metals, non-ferrous metals and combinations thereof.Suitable ferrous metals include iron, steel, and alloys thereof.Nonlimiting examples of useful steel materials include cold rolledsteel, galvanized (zinc coated) steel, electrogalvanized steel,stainless steel, pickled steel, zinc-iron alloy such as GALVANNEAL,GALVALUME and GALFAN zinc-aluminum alloys, and combinations thereof.Useful non-ferrous metals include aluminum, zinc, magnesium and alloysthereof. Combinations or composites of ferrous and non-ferrous metalscan also be used.

[0079] The composition of the present invention having sealing and sounddampening properties can be applied to a metallic substrate using any ofa variety of application methods known in the art. For example, thecomposition can be applied to a metallic substrate via spray andextrusion techniques.

[0080] The application viscosity of the sealing and sound dampeningcompositions of the present invention can be less than 120 seconds, andtypically less than 100 seconds, for 20 grams of the compositionextruded by a Caster-Sievers rheometer (having a 0.125 inch diameter anda 2 inch long orifice) at 40 psi, and a composition temperature afterextrusion of 77° F. (25° C.).

[0081] After application as described above, the composition of thepresent invention is cured. The inventive composition can be cured atambient temperature, a combination of ambient and thermal curingconditions, or at thermal conditions only. Specific curing times andtemperatures depend on the application conditions and the nature of thecuring agent(s). For example, in a “real life” application, thecomposition of the present invention can be cured in electrocoat and/ortop coat curing ovens in an automotive assembly plant.

[0082] The cured composition can have a sound dampening value greaterthan 0.030, typically greater than 0.080 Oberst dissipation factor. Forpurposes of the present invention, Oberst dissipation factor is measuredat 200 Hz and 25° C. in accordance with ASTM E-756-98.

[0083] As previously mentioned, one of the major benefits of thecomposition of the present invention is that it can be applied in a bodyshop area of an automotive assembly plant. By applying the compositionin the body shop, any dirt, fingerprints, and/or overspray on anautomotive part can be washed away in the pretreatment wash cycle.

[0084] Depending on the end use of the automotive part onto which thecomposition of the present invention is applied, it may be desirable toenhance the corrosion resistance of a metallic substrate prior toapplication of the composition.

[0085] In one embodiment of the present invention, the corrosionresistance can be enhanced by applying the composition of the presentinvention over a layer of weldable primer, which has previously beenapplied to the substrate. Weldable primers are well known in the art forproviding corrosion resistance. Nonlimiting examples of weldable primersare those disclosed in U.S. Pat. Nos. 5,580,371; 5,652,024; 5,584,946;3,792,850, and GB Patent No. 2,237,812A.

[0086] In one particular embodiment of the present invention, theweldable primer layer can be formed from a weldable primer compositioncomprising (A) a resinous binder comprising (1) at least one functionalgroup containing polymer, and (2) at least one curing agent havingfunctional groups that are reactive with the functional groups of thefunctional group containing polymer (1); and (B) at least oneelectroconductive pigment dispersed in the resinous binder (A). Theweldable primer typically is formed from a thermoset composition whichis weldable when deposited and cured on a metallic substrate.

[0087] In the aforementioned weldable primer composition, the polymer(1) can comprise functional groups which include but are not limited tohydroxyl, amine, carbamate, carboxyl, epoxy, and urea groups. Typically,the functional group-containing polymer comprises one or more epoxygroup-containing polymers and/or one or more phosphatized epoxygroup-containing polymers.

[0088] Useful epoxy group-containing polymers have at least one epoxy oroxirane group in the molecule, such as polyglycidyl ethers of polyhydricalcohols. Useful polyglycidyl ethers of polyhydric alcohols can beformed by reacting epihalohydrins such as epibromohydrin, dichlorohydrinand epichlorohydrin with polyhydric alcohols, such as dihydric alcohols,in the presence of an alkali condensation and dehydrohalogenationcatalyst. Suitable alkali condensation and dehydrohalogenation catalystinclude sodium hydroxide or potassium hydroxide.

[0089] Suitable polyhydric alcohols can be aromatic, aliphatic orcycloaliphatic alcohols. Nonlimiting examples of suitable aromaticpolyhydric alcohols include phenols that are preferably at leastdihydric phenols. Other useful aromatic polyhydric alcohols includedihydroxybenzenes, for example resorcinol, pyrocatechol andhydroquinone; bis(4-hydroxyphenyl)-1,1-isobutane;4,4-dihydroxybenzophenone; bis(4-hydroxyphenyl)-1,1-ethane;bis(2-hydroxyphenyl)methane; 1,5-hydroxynaphthalene; 4-isopropylidenebis(2,6-dibromophenol); 1,1,2,2-tetra(p-hydroxy phenyl)-ethane;1,1,3-tris(p-hydroxy phenyl)-propane; novolac resins; bisphenol F;long-chain bisphenols; and 2,2-bis(4-hydroxyphenyl)propane, i.e.,bisphenol A.

[0090] Nonlimiting examples of aliphatic polyhydric alcohols includeglycols such as ethylene glycol, diethylene glycol, triethylene glycol,1,2-propylene glycol, 1,4-butylene glycol, 2,3-butylene glycol,pentamethylene glycol, polyoxyalkylene glycol; polyols such as sorbitol,glycerol, 1,2,6-hexanetriol, erythritol and trimethylolpropane; andmixtures thereof. An example of a suitable cycloaliphatic alcohol iscyclohexanedimethanol.

[0091] The epoxy group-containing polymer typically has at least twoepoxy groups per molecule and aromatic or cycloaliphatic functionalitywhich can improve adhesion to a metal substrate. Further, the epoxygroup-containing polymer can have a number average molecular weight(“Mn”) ranging from 220 to 25,000, as determined by gel permeationchromatography using a polystyrene standard.

[0092] Useful epoxy group-containing polymers can include thosedisclosed in U.S. Pat. Nos. 5,294,265; 5,306,526 and 5,653,823, whichare hereby incorporated by reference. Other useful epoxygroup-containing materials can include epoxy-functional acrylicpolymers, glycidyl esters of carboxylic acids and mixtures thereof.Examples of suitable commercially available epoxy group-containingpolymers can include those which are available from Shell ChemicalCompany under the tradename EPON® (e.g., EPON® 836, EPON® 828, EPON®1002F and EPON® 1004F).

[0093] Phosphatized group-containing polymers typically comprise areaction product of an epoxy group-containing polymer with a compoundcontaining phosphorus acid groups. Usually, the resulting reactionproduct comprises reactive functional groups.

[0094] The compound containing phosphorus acid groups which is reactedwith the epoxy group-containing polymer can comprise phosphonic acids,phosphorous acid, phosphoric acids (which are typically employed)including super- and poly-, and mixtures thereof.

[0095] Examples of suitable phosphonic acids include those having atleast one group of the structure:

—R—PO—(OH)₂

[0096] where R is —C—, usually CH₂, and typically O—CO—(CH₂)₂—.Nonlimiting examples of suitable phosphonic acids include1-hydroxyethylidene-1,1-diphosphonic acid, methylene phosphonic acids,and alpha-aminomethylene phosphonic acids containing at least one groupof the structure:

[0097] such as (2-hydroxyethyl)aminobis(methylene phosphonic) acid,isopropylaminobis(methylenephosphonic) acid and other aminomethylenephosphonic acids disclosed in U.S. Pat. No. 5,034,556 at column 2, line52 to column 3, line 43, which is hereby incorporated by reference.

[0098] Other useful phosphonic acids include alpha-carboxymethylenephosphonic acids containing at least one group of the structure:

[0099] Nonlimiting examples of suitable phosphonic acids can includebenzylaminobis(methylene phosphonic) acid, cocoaminobis(methylenephosphonic) acid, triethylsilylpropylamino(methylene phosphonic) acidand carboxyethyl phosphonic acid.

[0100] The equivalent ratio of the compound containing phosphorus acidgroups to epoxy group-containing polymer can be within the range of 0.3to 5.0:1, usually 0.5 to 3.5:1. The epoxy group-containing polymer andthe compound-containing phosphorus acid groups can be reacted togetherby any method known to those skilled in the art.

[0101] The functional groups associated with the reaction product of theepoxy group-containing polymer and the compound-containing phosphorusacid groups are hydroxyl groups including acidic hydroxyls or hydroxylgroups and epoxy groups depending on the equivalent ratio of thecompound containing phosphorus acid groups to epoxy group-containingpolymer.

[0102] The resinous binder of the weldable primer further comprises (2)a curing agent having functional groups that are reactive with thefunctional groups of the polymer (1) described above. The curing agent(2) can be selected from at least one of aminoplasts, polyisocyanates,including blocked isocyanates, polyacids, organometallic acid-functionalmaterials, polyamines, polyamides and mixtures of any of the foregoingdepending on the identity of the functional groups of the polymer (1).

[0103] Useful aminoplasts can be obtained from the condensation reactionof formaldehyde with an amine or amide. Nonlimiting examples of suitableamines or amides include melamine, urea and benzoguanamine.

[0104] Although condensation products obtained from the reaction ofalcohols and formaldehyde with melamine, urea or benzoguanamine are mostcommon, condensates with other amines or amides can be used. Forexample, aldehyde condensates of glycoluril, which yield a high meltingcrystalline product useful in powder coatings, can be used. Formaldehydeis the most commonly used aldehyde, but other aldehydes such asacetaldehyde, crotonaldehyde, and benzaldehyde can also be used.

[0105] The aminoplast can contain imino and methylol groups. In certaininstances, at least a portion of the methylol groups can be etherifiedwith an alcohol to modify the cure response. Any monohydric alcohol likemethanol, ethanol, n-butyl alcohol, isobutanol, and hexanol can beemployed for this purpose. Nonlimiting examples of suitable aminoplastresins are commercially available from Cytec Industries, Inc. under thetradename CYMEL® and from Solutia, Inc. under the trademark RESIMENE®.Specific examples of suitable aminoplasts include CYMEL® 385 (forwater-based compositions), CYMEL® 1158 imino-functional melamineformaldehyde condensates, and CYMEL® 303.

[0106] Other curing agents suitable for use in the weldable primerinclude polyisocyanate curing agents. As used herein, the term“polyisocyanate” is intended to include blocked (or capped)polyisocyanates as well as unblocked polyisocyanates. The polyisocyanatecan be aliphatic, aromatic, or a mixture of the foregoing. Althoughhigher polyisocyanates such as isocyanurates of diisocyanates are oftenused, diisocyanates can be used. Higher polyisocyanates also can be usedin combination with diisocyanates. Isocyanate prepolymers, for examplereaction products of polyisocyanates with polyols can also be used.Mixtures of polyisocyanate curing agents can be used.

[0107] If the polyisocyanate is blocked or capped, any suitablealiphatic, cycloaliphatic, or aromatic alkyl monoalcohol known to thoseskilled in the art can be used as a capping agent for thepolyisocyanate. Suitable capping agents include oximes and lactams.

[0108] Other useful curing agents comprise blocked polyisocyanatecompounds such as, for example, the tricarbamoyl triazine compoundsdescribed in detail in U.S. Pat. No. 5,084,541, which is incorporatedherein by reference.

[0109] Suitable curing agents are described in U.S. Pat. No. 4,346,143at column 5, lines 45-62 and include blocked or unblocked di- orpolyisocyanates such as toluene diisocyanate blocked with caprolactam. Atoluene diisocyanate blocked with caprolactam is commercially availablefrom Bayer Corporation as DESMODUR® BL 1265.

[0110] Suitable polyacid curing agents include acid group-containingacrylic polymers prepared from an ethylenically unsaturated monomercontaining at least one carboxylic acid group and at least oneethylenically unsaturated monomer that is free from carboxylic acidgroups. Such acid functional acrylic polymers can have an acid numberranging from 30 to 150. Acid functional group-containing polyesters canbe used as well. The above-described polyacid curing agents aredescribed in further detail in U.S. Pat. No. 4,681,811 at column 6, line45 to column 9, line 54, which is incorporated herein by reference.

[0111] Other suitable curing agents include organometallic complexedmaterials, for example, stabilized ammonium zirconium carbonate solutioncommercially available from Magnesium Elektron, Inc. as BACOTE™ 20,stabilized ammonium, zirconium carbonate, and a zinc-based polymercrosslinking agent commercially available from Ultra Additives Inc. asZINPLEX 15.

[0112] Nonlimiting examples of suitable polyamine curing agents includeprimary or secondary diamines or polyamines in which the radicalsattached to the nitrogen atoms can be saturated or unsaturated,aliphatic, alicyclic, aromatic, aromatic-substituted-aliphatic,aliphatic-substituted-aromatic, and heterocyclic. Nonlimiting examplesof suitable aliphatic and alicyclic diamines include 1,2-ethylenediamine, 1,2-propylene diamine, 1,8-octane diamine, isophorone diamine,propane-2,2-cyclohexyl amine, and the like. Nonlimiting examples ofsuitable aromatic diamines include phenylene diamines and toluenediamines, for example o-phenylene diamine and p-tolylene diamine. Theseand other suitable polyamines are described in detail in U.S. Pat. No.4,046,729 at column 6, line 61 to column 7, line 26, which isincorporated herein by reference.

[0113] Appropriate mixtures of curing agents may also be used in theweldable primer. The weight percent of the curing agent present in theweldable primer generally ranges from 5 to 60 percent based on the totalweight of resin solids present in the resinous binder.

[0114] The resinous binder of the weldable primer composition mayfurther comprise a catalyst to accelerate the crosslinking reaction orto promote the crosslinking reaction at a lower temperature. Selectionof suitable catalysts is dependent upon the particular functional groupspresent and are well known to those skilled in the art. Nonlimitingexamples of suitable catalysts for aminoplast reactions include acidicmaterials, for example, acid phosphates, such as phenyl acid phosphate,and substituted or unsubstituted sulfonic acids such as dodecylbenzenesulfonic acid and para-toluene sulfonic acid. Nonlimiting examples ofsuitable catalysts for reactions between isocyanate groups and activehydrogen-containing materials, for example, those comprising hydroxylgroups, include tin catalysts such as dibutyl tin dilaurate, dibutyl tindiacetate, and dibutyl tin oxide. Nonlimiting examples of epoxy acidbase catalysts include tertiary amines such as N,N′-dimethyldodecylamine catalysts.

[0115] The catalyst can also be a phosphatized polyester or aphosphatized epoxy. For example, the catalyst can be the reactionproduct of phosphoric acid and a bisphenol A diglycidyl ether having twohydrogenated phenolic rings, such as DRH-151, which is commerciallyavailable from Shell Chemical Co. When added to the other componentsthat form the weldable primer, the catalyst can be present in an amountranging from 0.1 to 5.0 percent by weight, and is typically present inan amount ranging from 0.5 to 1.5 percent by weight based on the totalweight of resin solids present in the weldable primer.

[0116] As stated above, the weldable primer further comprises (B) atleast one electroconductive pigment to render the compositionelectrically conductive and spot-weldable. Suitable electroconductivepigments include electrically conductive carbon black pigments.Generally, the carbon blacks can be any one or a blend of carbon blacksranging from those that are known as higher conductive carbon blacks,i.e. those with a BET surface area greater than 500 m²/gram and DBPadsorption number (determined in accordance with ASTM D2414-93) of 200to 600 ml/100 grams to those with lower DBP numbers on the order of 30to 120 ml/l 00 gram such as those with DBP numbers of 40 to 80 ml/l 00grams.

[0117] Examples of commercially available electroconductive carbon blackpigments include Cabot Monarch™ 1300, Cabot XC-72R, Black Pearls 2000and Vulcan XC 72 sold by Cabot Corporation; Acheson Electrodag™ 230 soldby Acheson Colloids Co.; Columbian Raven™ 3500 sold by Columbian CarbonCo.; and Printex™ XE 2, Printex 200, Printex L and Printex L6 sold byDeGussa Corporation, Pigments Group. Suitable carbon blacks are alsodescribed in U.S. Pat. No. 5,733,962.

[0118] Also, electrically conductive silica pigments may be used.Suitable examples include AEROSIL 200 sold by Japan Aerosil Co., Ltd.,and SYLOID® 161, SYLOID® 244, SYLOID® 308, SYLOID® 404 and SYLOID® 978,all available from Fuji Davison Co., Ltd.

[0119] Other electrically conductive pigments can be used. For example,metal powders such as aluminum, copper or special steel, molybdenumdisulphide, iron oxide, e.g., black iron oxide, antimony-doped titaniumdioxide and nickel doped titanium dioxide can be used.

[0120] Particles coated with metals such as cobalt, copper, nickel,iron, tin, zinc, and combinations of thereof are also useful. Particleswhich can be coated with the aforementioned metals include alumina,aluminum, aromatic polyester, boron nitride, chromium, graphite, iron,molybdenum, neodymium/iron/boron, samarium cobalt, silicon carbide,stainless steel, titanium diboride, tungsten, tungsten carbide, andzirconia particles. The aforementioned metal-coated particles arecommercially available from Advanced Ceramics Corp.

[0121] Other metal-coated particles which may be used advantageously inthe weldable primer include ceramic microballoons, chopped glass fibers,graphite powder and flake, boron nitride, mica flake, copper powder andflake, nickel powder and flake, aluminum coated with metals such ascarbon, copper, nickel, palladium, silicon, silver and titaniumcoatings. These particles are typically metal-coated using fluidized bedchemical vacuum deposition techniques. Such metal-coated particles arecommercially available from Powdermet, Inc. Mixtures of differentelectroconductive pigments can be used.

[0122] The electroconductive pigment also can be selected from at leastone of ferrophosphorous, zinc, tungsten and mixtures thereof. Theelectroconductive pigment typically is dispersed in the resinous bindersuch that the weight ratio of electroconductive pigment to resinousbinder is within the range of 1.0 to 6.0:1. Zinc and ferrophosphorouscan also be used either alone or in combination as the electroconductivepigment.

[0123] When tungsten is used as the electroconductive pigment, thetungsten is dispersed in the resinous binder such that the weight ratioof electroconductive pigment to resinous binder is within the range of0.1 to 4.0:1, typically within the range of 0.75 to 1.25:1. Higherlevels of tungsten can be used if desired.

[0124] Suitable zinc pigments are commercially available from ZINCOLIGmbH as trademark ZINCOLIS® 620 or 520. Suitable iron phosphidepigments, also referred to as ferrophosphorus, are commerciallyavailable from Occidental Chemical Corporation under the tradenameFERROPHOS™.

[0125] The electroconductive pigment is dispersed in the resinous binderin an amount such that when the weldable primer is deposited and curedon a metallic substrate, the weldable primer is sufficientlyelectroconductive to sustain a spot welding and joining operation asused in an automotive assembly plant. Typically, the weight ratio of theelectroconductive pigment to the resinous binder is within the range of0.2 to 10, and often within the range of 1.0 to 6.0:1.

[0126] The weldable primer may further comprise one or more corrosioninhibitive materials, for example, corrosion resistant pigments.Suitable corrosion resistant pigments include, but are not limited to,zinc phosphate, calcium ion-exchanged silica, colloidal silica,synthetic amorphous silica, and molybdates such as calcium molybdate,zinc molybdate, barium molybdate, strontium molybdate, and mixturesthereof. Suitable calcium ion-exchanged silica is commercially availablefrom W. R. Grace & Co. as SHIELDEX® AC3. Suitable colloidal silica isavailable from Nissan Chemical Industries, Ltd. under the tradenameSNOWTEX®. Suitable amorphous silica is available from W. R. Grace & Co.under the tradename SYLOID®.

[0127] The weldable primer can further comprise other optionalingredients such as inorganic lubricants, for example, molybdenumdisulfide particles which are commercially available from ClimaxMolybdenum Marketing Corporation. The weldable primer can also includeextender pigments such as iron oxides and iron phosphides, flow controlagents, and thixotropic agents such as silica, montmorillonite clay, andhydrogenated castor oil. Further, the weldable primer can includeanti-settling agents such as aluminum stearate and polyethylene powder,dehydrating agents which inhibit gas formation, such as silica, lime orsodium aluminum silicate, and wetting agents including salts of sulfatedcastor oil derivatives such as those commercially available from CognisCorporation under the trademark RILANIT® R4.

[0128] Generally, the weldable primer is essentially free ofchromium-containing materials, i.e., contains less than 2 weight percentof chromium-containing materials (expressed as CrO₃), often less than0.05 weight percent, and typically about 0.00001 weight percent based onthe weight of total solids present in the composition. Examples of suchchromium-containing materials include chromic acid, chromium trioxide,chromic acid anhydride, dichromate salts such as ammonium dichromate,sodium dichromate, potassium dichromate, and calcium chromate.

[0129] The weldable primer may contain a diluent to adjust the viscosityof the coating composition. Useful diluents include water, organicsolvents, or mixtures of water and organic solvents. If a diluent isused, it should not detrimentally affect the adhesion of the curablecoating composition to the metal substrate.

[0130] When water is used as the diluent (“aqueous weldable primer”), itmay be necessary to include additives such as dispersants, thickeners,stabilizers, rheology modifiers, and anti-settling agents in theweldable primer. A suitable rheology modifier is RM-8 which iscommercially available from Rohm and Haas Company. A suitable dispersingagent and/or stabilizer is potassium tripolyphosphate (KTPP).

[0131] Typically, an aqueous weldable primer has a viscosity rangingfrom 100 to 2000 centipoise as determined using a Brookfield Cone andPlate viscometer. Depending on the application method which will be usedto apply the weldable primer, it may be necessary to further reduce theviscosity of the weldable primer by adding more water and/or organicsolvent.

[0132] Aqueous weldable primer compositions can also contain an amine.For example, hydroxyl group-containing amines such as dimethanolamne anddiisopropanolamine are suitable. The volatile organic compound (VOC)content of the aqueous composition can be less than 2; typically, it isless than 1.7.

[0133] Optionally, the aqueous weldable primers can comprise one or moresurfactants to improve the ability of the coating to wet the substrate(i.e., to form a continuous coating thereover). Generally, surfactantsare present in an amount of less than 2 weight percent based on totalweight of the coating composition. Suitable surfactants are commerciallyavailable from Air Products and Chemicals, Inc. under the tradenameSURFYNOL®.

[0134] The diluent can be an organic solvent (“organic solvent-basedweldable primer”). For example, alcohols having up to about 8 carbonatoms, such as ethanol and isopropanol; alkyl ethers of glycols, such as1-methoxy-2-propanol, and monoalkyl ethers of ethylene glycol,diethylene glycol and propylene glycol are suitable diluents. Apropylene glycol monomethyl ether or a dipropylene glycol monomethylether such as those commercially available from Dow Chemical Company asDOWANOL® PM and DOWANOL® DPM, respectively, are well known diluents.

[0135] Organic solvent-based weldable primers generally have a viscosityranging from 100 to 2000 centipoise as determined using a BrookfieldCone and Plate viscometer. If necessary, the viscosity of the weldableprimer may be further reduced using a suitable organic diluent.

[0136] The organic solvent-based weldable primer can further include anamine for stability purposes. For example, alkyl substituted morpholinecompounds such as N-methyl and N-ethyl morpholine are suitable.

[0137] Other suitable organic solvents include ketones such ascyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone andisophorone; esters and ethers such as 2-ethoxyethyl acetate, propyleneglycol methyl ether acetates such as DOWANOL® PM ACETATE which iscommercially available from Dow Chemical Company; and aromatic solventssuch as toluene, xylene, aromatic solvent blends derived from petroleumsuch as those available under the trademark SOLVESSO®.

[0138] Exemplary of a suitable commercially available weldable primer isBONAZINC®, a zinc rich, mill applied, organic, film-forming compositionwhich is commercially available from PPG Industries, Inc.

[0139] When in aqueous form, the weldable primer composition pHgenerally ranges from 7.0 to 12.0, and typically from 8.0 to 10.5. Ifnecessary, water-soluble or water-dispersible acids and/or bases can beused to adjust the pH. Suitable acids include inorganic acids, such ashydrofluoric acid, fluoroboric acid, phosphoric acid, and nitric acid;organic acids, such as lactic acid, acetic acid, hydroxyacetic acid,citric acid; and mixtures thereof. Suitable bases include inorganicbases, such as sodium hydroxide and potassium hydroxide;nitrogen-containing compounds such as ammonia, triethylamine, methylethanol amine, diisopropanolamine; and mixtures thereof.

[0140] The weldable primer composition can be applied to the surface ofan untreated or treated and/or coated metallic substrate by anyconventional application technique known in the art, such as byspraying, immersion, or roll coating in a batch or continuous process.Squeegee or wringer rolls can be used to remove excess weldable primercomposition. After the weldable primer composition is applied onto ametallic substrate, it typically is thermally cured.

[0141] As used herein, by “cured” is meant that any crosslinkablecomponents of the weldable primer are at least partially crosslinked.The crosslink density of the crosslinkable components, i.e., the degreeof crosslinking, ranges from 5 percent to 100 percent of completecrosslinking. The crosslink density can be determined by a variety ofmethods including mechanical thermal analysis (DMTA) techniques.

[0142] Curing can be achieved at peak metal temperatures ranging from100° C. to 400° C. Peak metal temperatures ranging from 130° C. to 260°C. are typical. Suitable cure times (i.e., oven dwell times) can varywidely, and can range from twenty (20) seconds to sixty (60) seconds.

[0143] The dry film thickness of the weldable primer layer generallydepends on the application conditions. In order to provide sufficientcorrosion resistance for a metallic substrate which will be used as anautomotive part, the dry film thickness of the weldable primer layermust be at least 1 micrometer (about 0.04 mils), often 1 to 20micrometers, and typically 2 to 10 micrometers. Depending on thespecific chemical makeup of the substrate and the end use of thesubstrate, it may be necessary to increase or decrease the dry filmthickness of the weldable primer layer.

[0144] The following Examples are illustrative of the present inventionand are not intended to limit the scope of the present invention.

EXAMPLES

[0145] The present invention will be further illustrated by thenonlimiting examples below. Table 1 contains compositional data forExamples 1-13 which exemplify various embodiments of the compositionhaving sealing and sound dampening properties according to the presentinvention. Table 2 contains the results of the Ford Corrosion Test forsubstrates containing the compositions of Examples 1-11 when theexemplary composition was underbaked (“underbake case”). Table 3contains the results of the Ford Corrosion Test for substratescontaining the compositions of Examples 1-11 when the exemplarycomposition was overbaked (“overbake case”). Table 4 contains theresults of substrates containing the compositions of Examples 12-14 whensubjected to the Chrysler Corrosion Test. Examples 12-14 demonstrate thecorrosion resistance of the substrates when the inventive composition isapplied over a layer of weldable primer. Examples 12-14 were i 5 appliedover a galvanized panel and over a galvanized panel coated with a layerof weldable primer. Table 5 shows the “under” and “over” bake schedulesfor different embodiments of the present invention. Table 6 reflects thesound dampening performance of selected exemplary compositions byrecording Oberst dissipation data.

[0146] In the examples below, Example 2 is a comparative example.Example 2 is sealant/sound dampener which is commercially available fromPPG Industries, Inc. under the trade name P7912. TABLE 1 CompositionalData for Various Embodiments of the Composition Having Sealing and SoundDampening Performance Properties According to the Present Invention Ex.1 Ex. 2* Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex.12Ex. 13 EPON 828¹ 20.4 20.6 20.6 20.5 20.5 20.5 20.5 17.6 17.6 17.6 20.120.1 Epoxidized Dimer 2.3 15.9 15.9 15.8 15.8 15.8 15.8 13.6 13.6 13.6Acid² ERISYS GE-35³ 5.4 15.5 15.5 DER736⁴ 1.3 CARDOLITE 9.9 4.9 4.9 4.84.8 4.8 4.8 6.4 6.4 6.4 3.6 3.6 NC-513⁵ PoIyester⁶ 8.0 18.6 18.6 18.615.9 15.9 15.9 18.3 18.3 Polyester⁷ 18.7 18.7 18.6 TRILENE 65⁸ 3.3 2.02.0 2.0 2.0 2.0 4.0 1.7 1.7 1.7 1.9 1.9 Dicy⁹ 2.5 2.1 2.1 2.1 2.1 2.92.9 1.8 1.8 1.8 2.0 2.0 Diuron¹⁰ 1.3 0.6 0.6 0.6 0.6 0.9 0.9 0.5 0.5 0.50.6 0.6 Mica, C-3000¹¹ 36.2 31.7 31.7 31.4 31.4 31.4 31.4 27.0 27.0 27.026.2 26.2 EPS-200¹² 3.3 INHIBICIL¹³ 0.5 0.7 0.7 K-SPERSE 6501¹⁴ 0.5 0.7WAYCOR 204¹⁵ 3.0 0.9 Q-CEL 640¹⁶ 2.0 2.0 2.0 2.0 2.0 2.0 WINNOFIL SPT¹⁷6.8 6.8 6.8 7.8 7.8 CABOSIL M-5¹⁸ 1.0 0.8 0.8 0.8 1.0 1.0 BENTONE 27¹⁹1.1 1.2 1.2 2.0 2.0 2.0 2.0 2.5 2.5 2.5 1.9 1.9 BENTONE 38²⁰ 2.5 TALC40-27²¹ 5.1 5.1 5.1 RAVEN 410²² 0.1 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.30.3 0.3 CaO²³ 0.4

[0147] Table 2 and 3 show the results of substrates containing variousembodiments of the inventive composition when subjected to the FordCorrosion Test¹. Table 2 shows the underbake case, and Table 3 shows theoverbake case. See Table 5 for the “under” bake schedules. TABLE 2RESULTS OF THE FORD CORROSION TEST-UNDERBAKE CASE Examples 1 2* 3 4 5 67 8 9 10 11 Predominant adh² coh⁴ tcf⁶ coh coh coh coh tfc (easy coh/tfccoh (1- Failure Mode to fit) (slight lift) 2 mm from edge; adh Blistersdue None None None None None None Slight to exposure UndercuttingComplete 30 5-7 20-25 3-5 4-8 2-3 from the release from edge (mm)-4″substrate³ wide- intrusion into the coating along with short side of a4″ × 12′ panel Undercutting Complete 10-15 5-7 10-15 3-8 5-10 2-3 No NoNo from the release from corrosion corrosion corrosion edge (mm)-substrate 12″ wide- intrusion into the coating along the long side of a4″ × 12″ panel Undercutting Complete 40 10 25-30 7-10 3-8 2-5 from therelease from corner (mm)- substrate² intrusion into the coating at thecorner of the panel Color of the gray-brown white, gray, gray, brown,gray, gray, Undercut gray, dark brown gray brown brown Metal brown gray

[0148] TABLE 3 RESULTS OF THE FORD CORROSION TEST-OVERBAKE CASE Examples1 2* 3 4 5 6 7 8 9 10 11 Predominant adh coh tfc coh coh coh coh coh(2-3 coh (1-2 coh (1-2 Failure Mode mm from mm from mm from edge edgeedge adh) adh) adh) Blisters due severe none none none none severeslight to exposure Undercutting 10-40 10-12 5-7 5-7 3-5 2-5 2-4 from theedge (mm)-4″ wide Undercutting 10-15 8-10 5 5-7 0-2 0-2 2-4 No No Nofrom the corrosion corrosion corrosion edge (mm)- 12″ Undercutting 10-1515-20 5 5-8 5-8 3-5 2-4 from the corner (mm) Color of the gray whitegray, brown, gray, gray, gray, Undercut and dark gray brown brown brownMetal gray gray

[0149] TABLE 4 RESULTS OF THE CHRYSLER CORROSION TEST¹ Examples 12 13 2*COATING APPLIED OVER A GALVANIZED METAL PANEL Corrosion none none noneUndercutting (mm) 3-4 3-4 almost total COATING APPLIED OVER A GALVANIZEDPANEL COATED WITH A WELDABLE PRIMER (BONAZINC) WHICH IS COMMERCIALLYAVAILABLE FROM PPG Corrosion none none none Undercutting (mm) none nonenone

[0150] TABLE 5 UNDERBAKE AND OVERBAKE SCHEDULES FOR THE EXEMPLARYCOMPOSITIONS Example Underbake Schedule Overbake Schedule  1 60 minutesat 335° F. followed 60 minutes at 375° F. by 20 minutes at 330° F.followed by 30 minutes at 250° F.  2* 60 minutes at 335° F. followed 60minutes at 375° F. by 20 minutes at 330° F. followed by 30 minutes at250° F.  4 30 minutes at 325° F. 60 minutes at 400° F.  5 30 minutes at325° F. 60 minutes at 400° F.  8 30 minutes at 325° F. 60 minutes at380° F. 11 30 minutes at 325° F. 60 minutes at 380° F. 12 30 minutes at325° F. 60 minutes at 380° F. 13 30 minutes at 325° F. 60 minutes at380° F.

[0151] TABLE 6 Oberst Dissipation Data¹ for Selected Examples OberstDissipation Factor Oberst Dissipation Factor Example Underbake CaseOverbake Case  1 0.09 0.09  2* 0.13 0.10  4 0.15 0.10  5 0.13 0.08  80.14 0.07 11 0.11 0.04 12 0.11 0.07 13 0.11 0.09

[0152] As can be seen from the experimental results above, thecompositions of the present invention provide superior sealing and sounddampening properties. When the composition of the present invention wasapplied over a metallic substrate coated with a weldable primer, therewas little or no corrosion and no undercutting. Depending on the desiredend-use of the automotive part or other substrate onto which theinventive composition is applied, the specific formulation of theinventive composition can vary.

[0153] Whereas particular embodiments of this invention have beendescribed above for purposes of illustration, it will be evident tothose skilled in the art the numerous variations of the details of thepresent invention may be made without departing from the invention asdefined in the appended claims.

What is claimed is:
 1. A composition having improved sealing and sounddampening properties comprising: (a) one or more polyepoxides comprisingat least two epoxide groups per molecule; (b) a thermoplastic polyesterpolymer; (c) a curing agent adapted to react with the polyepoxides; (d)inorganic particles having an oil absorption value of less than 70 asdetermined in accordance with ASTM D 281-95; and (e) inorganicmicroparticles different from the inorganic particles (d), the inorganicmicroparticles having an average particle size prior to incorporationinto the composition ranging from 0.5 to 200 microns.
 2. The compositionaccording to claim 1, wherein the polyepoxides comprise epoxypolyethers.
 3. The composition according to claim 1, wherein thepolyepoxides comprise polyglycidyl ethers of polyhydric alcohols.
 4. Thecomposition according to claim 1, wherein the polyepoxides arepolyglycidyl esters of polycarboxylic acids.
 5. The compositionaccording to claim 1, wherein the polyepoxides are derived byepoxidating olefinically unsaturated alicyclic compounds.
 6. Thecomposition according to claim 1, wherein the polyepoxides containoxyalkylene groups in the epoxy molecule.
 7. The composition accordingto claim 1, wherein the polyepoxides comprise epoxy novolac resins. 8.The composition according to claim 1, wherein the polyepoxide is presentin an amount ranging from 15 to 50 weight percent based on the totalweight of the composition.
 9. The composition according to claim 1,wherein the thermoplastic polyester polymer is substantially free ofaromatic units.
 10. The composition according to claim 1, wherein thethermoplastic polyester polymer is present in an amount ranging from 3to 30 weight percent based on the total weight of the composition. 11.The composition according to claim 1, wherein said curing agent is analiphatic, cycloaliphatic, or aromatic polyfunctional amine.
 12. Thecomposition according to claim 1, wherein said curing agent is presentin the composition in an amount ranging from 1 to 50 percent by weight,based on the total weight of the composition.
 13. The compositionaccording to claim 1, wherein the inorganic particles are selected fromparticles having a spherical morphology, irregular morphology, or platymorphology, needle shaped, and mixtures thereof.
 14. The compositionaccording to claim 1, wherein the inorganic particles have a particlesize prior to incorporation into the composition ranging from 5 to 200microns.
 15. The composition according to claim 1, wherein the inorganicparticles comprise mica, calcium carbonate, dolomite, talc, and/orcalcium metasilicate.
 16. The composition according to claim 1, whereinthe inorganic particles are present in an amount ranging from 15 to 50weight percent based on the total weight of the composition.
 17. Thecomposition according to claim 1 that is capable of being spray applied.18. The composition according to claim 1 further comprising one or morealkylene diene copolymers.
 19. The composition according to claim 1,wherein the inorganic microparticles comprise colloidal silica, calciummodified precipitated silica, ion exchange silica gel, colloidalalumina, colloidal zirconia, and mixtures thereof.
 20. The compositionaccording to claim 1 further comprising one or more metallic compoundscomprising a cation selected from zinc, aluminum, magnesium, calcium,strontium, titanium, zirconium, cesium, yttrium, and iron cations; andan anion selected from phosphate, polyphosphate, phosphite, molybdate,sulfonate, tungstate, borate, borosilicate, silicate, and cyanamide. 21.A multilayer composite comprising a weldable primer layer formed from aweldable primer composition, and a second layer having improved sealingand sound dampening properties formed from a second composition over atleast a portion of the weldable primer layer, the second compositioncomprising: (a) one or more polyepoxides comprising at least two epoxidegroups per molecule; (b) a thermoplastic polyester polymer; (c) a curingagent adapted to react with the polyepoxide (a); (d) inorganic particleshaving an oil absorption value of less than 70 as determined inaccordance with ASTM D 281-95; and (e) inorganic microparticiesdifferent from the inorganic particles (d), the inorganic microparticleshaving an average particle size prior to incorporation into thecomposition ranging from 0.5 to 200 microns.
 22. The multilayercomposite according to claim 21, wherein the weldable primer layer isformed from a weldable primer composition comprising: (A) a resinousbinder comprising: (1) at least one functional group-containing polymer,and (2) at least one curing agent having functional groups reactive withthe functional groups of (1); and (B) at least one electroconductivepigment dispersed in resinous binder (A).
 23. A coated metallicsubstrate comprising: a metallic substrate, and a composition havingsealing and sound dampening properties over at least a portion of thesubstrate, said composition comprising: (a) one or more polyepoxidescomprising at least two epoxide groups per molecule; (b) a thermoplasticpolyester polymer; (c) a curing agent adapted to react with thepolyepoxides (a); (d) inorganic particles having an oil absorption valueof less than 70 as determined in accordance with ASTM D 281-95; and (e)inorganic microparticles different from the inorganic particles (d), theinorganic microparticles having an average particle size prior toincorporation into the composition ranging from 0.5 to 200 microns. 24.The substrate according to claim 23, wherein the polyepoxide comprisesan epoxy polyether.
 25. The substrate according to claim 23, wherein thepolyepoxide comprises a polyglycidyl ether of polyhydric alcohol. 26.The substrate according to claim 23, wherein the polyepoxide comprises apolyglycidyl ester of polycarboxylic acid.
 27. The substrate accordingto claim 23, wherein the polyepoxide is derived by epoxidatingolefinically unsaturated alicyclic compounds.
 28. The substrateaccording to claim 23, wherein the polyepoxide contains oxyalkylenegroups in the epoxy molecule.
 29. The substrate according to claim 23,wherein the thermoplastic polyester polymer is present in an amountranging from 3 to 30 weight percent based on the total weight of thecomposition.
 30. The substrate according to claim 23, wherein theinorganic particles are selected from particles having a sphericalmorphology, irregular morphology, platy morphology, needle shaped, andmixtures thereof.
 31. The substrate according to claim 23, wherein theinorganic particles have a particle size prior to incorporation into thecomposition ranging from 5 to 200 microns.
 32. The substrate accordingto claim 23, wherein the composition further comprises one or morealkylene diene copolymers.
 33. The substrate according to claim 23,wherein the inorganic microparticles comprise colloidal silica, calciummodified precipitated silica, ion exchange silica gel, colloidalalumina, colloidal zirconia, and mixtures thereof.
 34. The substrateaccording to claim 23, wherein the composition further comprises one ormore metallic compounds comprising a cation selected from zinc,aluminum, magnesium, calcium, strontium, titanium, zirconium, cesium,yttrium, and iron cations; and an anion selected from phosphate,polyphosphate, phosphite, molybdate, sulfonate, tungstate, borate,borosilicate, silicate, and cyanamide.
 35. A coated metallic substratecomprising: a metallic substrate; a weldable primer layer formed from aweldable primer composition deposited over at least a portion of thesubstrate; and a second layer formed from a second composition havingsealing and sound dampening properties deposited over at least a portionof the weldable primer layer, the second composition comprising: (a) oneor more polyepoxides comprising at least two epoxide groups permolecule; (b) a thermoplastic polyester polymer; (c) a curing agentadapted to react with the polyepoxides (a); (d) inorganic particleshaving an oil absorption of less than 70; and (e) inorganicmicroparticles different from the inorganic particles (d), the inorganicmicroparticles having an average particle size prior to incorporationinto the composition ranging from 0.5 to 200 microns.
 36. The coatedmetallic substrate of claim 35, wherein the metallic substrate isselected from the group comprising ferrous metal, non-ferrous metal, andcombinations thereof.
 37. The coated metallic substrate according toclaim 35, wherein the polyepoxide comprises an epoxy polyether.
 38. Thecoated metallic substrate according to claim 35, wherein the polyepoxidecomprises a polyglycidyl ether of polyhydric alcohol.
 39. The coatedmetallic substrate according to claim 35, wherein the polyepoxidecomprises a polyglycidyl ester of polycarboxylic acid.
 40. Thecomposition according to claim 35, wherein the polyepoxide is derived byepoxidating olefinically unsaturated alicyclic compounds.
 41. The coatedmetallic substrate according to claim 35, wherein the second compositionfurther comprises one or more alkylene diene copolymers.
 42. The coatedmetallic substrate according to claim 35, wherein the inorganicmicroparticles comprise colloidal silica, calcium modified precipitatedsilica, ion exchange silica gel, colloidal alumina, colloidal zirconia,and mixtures thereof.
 43. The coated metallic substrate according toclaim 35, wherein the second composition further comprises one or moremetallic compounds comprising a cation selected from zinc, aluminum,magnesium, calcium, strontium, titanium, zirconium, cesium, yttrium, andiron cations, and an anion selected from phosphate, polyphosphate,phosphite, molybdate, sulfonate, tungstate, borate, borosilicate,silicate, and cyanamide.
 44. The composition according to claim 35,wherein the first weldable primer layer is formed from a weldable primercomposition comprising: (A) a resinous binder comprising: (1) at leastone functional group-containing polymer, and (2) at least one curingagent having functional groups reactive with the functional groups of(1); and (B) at least one electroconductive pigment dispersed inresinous binder (A).
 45. A method for forming a coating having sealingand sound dampening properties on a metallic substrate comprising thesteps of: (a) providing a metallic substrate having two major surfaces;(b) applying a composition to at least a portion of one of the majorsurfaces of the substrate, said composition comprising: (1) one or morepolyepoxides comprising at least two epoxide groups per molecule; (2) athermoplastic polyester polymer; (3) a curing agent adapted to reactwith the polyepoxides (1); (4) inorganic particles having an oilabsorption value of less than 70 as determined in accordance with ASTM D281-95; and (5) inorganic microparticles different from the inorganicparticles (4), the inorganic microparticles having an average particlesize prior to incorporation into the composition ranging from 0.5 to 200microns; and (c) curing the applied composition, wherein the coatedsubstrate of step (c) has a sound dampening value greater than 0.030Oberst dissipation factor as measured at 200 Hz at 25° C. in accordancewith ASTM E-756-98.
 46. The method according to claim 45, wherein thecured composition has a dry film thickness ranging from 10 to 300 mils(250 to 7,500 micrometers).
 47. The method according to claim 45,wherein the substrate of step (c) is heated to a temperature rangingfrom 90° C. to 180° C.
 48. In a composition having sealing and sounddampening properties comprising: (a) one or more polyepoxides comprisingat least two epoxide groups; (b) a thermoplastic polyester polymer; (c)a curing agent adapted to react with the polyepoxide (a); and (d)inorganic particles having an oil absorption value of less than 70 asdetermined in accordance with ASTM D 281-95, the improvement comprisingthe inclusion in the composition of inorganic microparticles differentfrom the inorganic particles (d) in an amount sufficient to providecorrosion resistance properties as measured in accordance with ChryslerTest Method LP-463PB-10-01 which are superior to the corrosionresistance properties of the same composition which does not containsaid inorganic microparticles, the inorganic microparticles having anaverage particle size prior to incorporation into the compositionranging from 0.5 to 200 microns.
 49. The composition in accordance withclaim 48, wherein the inorganic microparticles are selected from thegroup consisting of mica, calcium carbonate, dolomite, talc, calciummetasilicate and mixtures thereof.
 50. The composition in accordancewith claim 48, wherein the inorganic microparticles have a particle sizeprior to incorporation into the composition ranging from 3 to 150microns.
 51. The composition in accordance with claim 48, wherein theinorganic microparticles are present in the composition in an amountranging from 0.1 to 5 weight percent based on the total weight of thecomposition.